We are using oracle 10g in a Solaris box. The same box has Informatica also installed. But it runs on port 6001. But whenever the server is restarted the Oracle database picks up the port 6001 and does not allow Informatica to be started. But I am have no clue of which Oracle process is using this port. I had confirmed that Oracle is using that particular port, by shutting down and starting up the database.